Fire alarm switch tripping mechanism



Oct. 27, 1942.l E, KQONTZ 2,299,828

FIRE ALARM SWITCH TRIPPING MECHANISM Filed ocyle, 1941 IN VEN TOR.

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AITDRNEYE Patented Oct. 27, 1942 UNITED STATES PATENT OFFICE FIRE ALARM SWITCH TRIPPING MECHANISM Charles E. Koontz, Baltimore, Md.

Application October 16, 1941, Serial No. 415,308

(Cl. 20D-5.4)

3 Claims.

This invention relates to a re alarm switch tripping mechanism and has for an object to provide mechanism including a spring pressed hook on the inside of the outer door of a conventional re alarm box and an angular lever pivoted on the inner face of one wall of the box bearing against the pivoted switch handle of a conventional switch which controls an alarm bell circuit, the arrangement being such that when the outer door is opened to turn in an alarm the hook will rock the lever to close the switch so that an audible alarm, such as a bell disposed exteriorly of the fire alarm box, will be sounded, and will remain in operation until the firemen arrive on the scene and manually open the switch, the purpose being to form an additional aid to the fire department in quickly arriving at a fire alarm box which has been pulled to summon the fire department.

A further object is to provide apparatus of this character which will be formed of a few strong, simple and durable parts, which will be inexpensive to manufacture, and which will not 4easily get out of order.

With the above and other objects in View the invention consists of certain novel details of construction and combinations of parts hereinafter fully described and claimed, it being understood that various modifications may be resorted to within the scope of the appended claims without departing from the spirit or sacrificing any of the advantages of the invention.

In the accompanying drawing forming a part of this specification:

Figure l is a front elevation of a fire alarm box equipped with fire alarm switch tripping mechanism, and an audible alarm device, controlled by the switch, constructed in accordance with the invention.

Figure 2 is a side elevation of the fire alarm box and alarm device shown in Figure 1.

Figure 3`is a cross sectional view taken on the line 3-3 of Figure 1 showing the switch tripping mechanism in top plan.

Figure 4 is a cross sectional view taken on the line 4-4 of Figure 3 showing the switch tripping mechanism, in side elevation, in normal positionr and showing diagrammatically the electrical connections of the alarm.

Figure 5 is a View similar to Figure 4 but showing the outer door open and the switch tripped to close the alarm circuit.

Referring now to the drawing in which like characters of reference designate similar parts box, II the housing of the key I2 which retracts the spring pressed locking bolt of the hinged front door I-3 when the glass I4 is broken, these parts being conventional. Included as part of the invention is an electric alarm bell I5 of conventional type disposed on top of a hollow post IB which is secured to the top of the lire alarm box in any preferred manner and carries the circuit wires Il for the alarm bell.

The invention comprises essentially a hook I8, see Figures 4 and 5, which is mounted on a pivot pin I9 carried by an angular bracket 20 having one leg secured to the inner surface of the outer door I3 of the ilre alarm box by screws 2I, see Figure 3. The hook is provided with a projection 22 which extends above the hook. A helical spring 23 is secured at one end by a pin 24 to the angular bracket 29 and at the other end is secured to a pin 25 carried by the projection 22. The spring tends to yieldably hold the hook depressed and in contact with a stop pin 26 carried by the angular bracket.

A conventional electric switch 2l of the tubular type is secured in an opening in one leg of an angular bracket 28 which is secured by screws 29 to the inner face of one end wall 30 of the re alarm box adjacent to the outer door 3l of the box, see Figures 4 and 5. The switch is provided with a pivot handle lever 32 which moves in a vertical plane to on and to oi position. A forked post 33 is secured to the angular bracket 28 by a nut 34 threaded onto a threaded stem 35 of the post, see Figure 4. The post is disposed directly above the handle lever 32 of the switch.

An angular trip lever 36 is pivotally secured at its elbow in the fork of the post by a pivot pin 3l. The lever has one arm normally engaged with the handle lever of the switch and the other arm is extended upwardly and is provided with a cam surface 38 over which the hook I8 on the door rides to lodge in rear of the upwardly extended arm of the angular trip lever to lodge in rear of the arm when the outer door of the lire alarm box is closed.

In operation when the outer door of the nre alarm box is opened to pull the alarm the hook I8 is carried forwardly with the door and rocks the angular trip lever 36 to swing the pivoted switch handle 32 downwardly and close the switch, during initial movement of the door to open position. The switch remains closed and since the alarm circuit wires ll are connected to the switch, and to a source of electricity 39, in the conventional manner, the alarm bell I5 will in the various Views, I0 designates a fire alarm 55 be sounded, and will continue to be, until the remen arrive after being aided in locating the box by the alarm, and manually move the switch handle to initial position to open the switch. When the outer door is again closed the hook I8 passes in rear of the upwardly extending arm of the angular lever 36 ready for the next operation.

From the above description it is thought thatl the construction and operation of the invention will be fully understood without` further explanation.

What is claimed is:

1. The alarm switch tripping mechanism for* i' re alarm boxes comprising an angular bracket j secured to the inner face of the outer door of the box, an angular bracket secured to the innerface of an end wall of the box near the door opening of the box, a pivoted spring pressedhook on the rst named bracket, a stop below the hooklirnfy iting downward movement of the hook, an 'angular lever pivoted on the second named bracket having one arm extending downwardly and having one arm extending upwardly and provided with a cam surface over which the hook rides to ,a position in rear of the arm when the door is closed, and, an alarm, switch having a pivoted switch handle engaging thefirst named arm of the angular lever, opening of the door moving the hook bodily forward to rock the angular lever and move the switch handle to close the switch. 2. An alarm switch tripping mechanism for re alarm boxes, comprising a spring pressed hook secured to the inner side of the outer door of the box, an angular lever pivotally secured interiorly of the box, said lever being disposed in position to permit the hook to pass over one arm of the lever in rear thereof when the door is closed, and an alarm switch adapted to be engaged by the other arm of the angular lever when ythe door is open for rocking the same.

3. An alarm switch tripping mechanism for re alarm boxes, comprising an angular bracket se- "cure'd' to the inner face of the outer door of the box, a bracket secured to the inner face of one end wall of the box near the door opening, a pivoted spring pressed hook on the angular bracket,

' "'a stop for limiting the downward movement of position in rear of the arm when the door is closed, and analarm switch engaging the rst 4named arm of the angular lever, whereby the hook-is rnovedbodily vforward to rock the angular lever to close the switchv when the door is open.

CHARLES E. KooNTz. 

